FDA Clears First Test for Detection of Carbapenem Resistance Genes in “Superbugs”

June 29, 2016

The U.S. Food and Drug Administration cleared for marketing the Xpert Carba-R Assay, an infection control aid that tests patient specimens to detect specific genetic markers associated with bacteria that are resistant to Carbapenem antibiotics.

Carbapenem antibiotics are widely used in hospitals to treat severe infections.

These resistant organisms are commonly referred to as Carbapenem-resistant Enterobacteriaceae, or CRE, and have been reported in almost all states within the U.S.

The Xpert Carba-R Assay is intended as an aid in infection control and can be used in conjunction with other clinical and laboratory findings.

Although the Xpert Carba-R Assay tests for the most prevalent carbapenemase genes associated with resistance to carbapenem antibiotics, it does not detect the bacteria, carbapenemase activity or other possible non-enzymatic causes of carbapenem resistance.

The Xpert Carba-R Assay tests only for genetic material.


  • Xpert Carba-R is an on-demand PCR test that detects and differentiates the most prevalent carbapenemases gene families (KPC, NDM, VIM, IMP-1 and OXA-48, now covering OXA-181 & OXA-232) in 48 minutes.
  • Xpert Carba-R provides rapid and accurate detection of CPO; giving you actionable information to help prevent outbreaks and help determine the best patient management pathway
  • Enhance your infection control program with Xpert Carba-R by identifying patients that are colonized with CPO quickly.
  • Xpert Carba-R identifies the specific genes that code for carbapenemase production that common culture methods alone cannot provide.
  • Even sophisticated culture methods would not reveal these results in a time frame that allows effective infection control interventions.
  • Xpert Carba-R delivers the best tool for surveillance, monitoring, and control of CPOs.


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Xpert Carba-R Assay also does not detect all types of carbapenemase genes, and it is important to recover bacteria for accurately tracking the spread of carbapenem resistance. Labs should continue to perform standard bacterial culture in conjunction with the Xpert Carba-R Assay. In addition, concomitant cultures are necessary to recover organisms for epidemiological typing, antimicrobial susceptibility testing, and for confirmatory bacterial identification.

The FDA’s decision to provide clearance was based on data from two clinical studies.

A prospective study used rectal swabs from 755 patients in hospitals or long-term care facilities to compare results from the Xpert Carba-R Assay with results from reference cultures and automated real-time polymerase chain reaction (PCR) sequencing.

A second study designed to test the clinical performance of the Xpert Carba-R Assay used 432 rectal swabs that were artificially prepared with specific concentrations of bacteria containing the genes detected by the test.

The results of these studies demonstrated similar performance between the Xpert Carba-R Assay and culture method.

The Xpert Carba-R Assay is manufactured by Cepheid, located in Sunnyvale, Calif.


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